The invention relates to an insert part having a water-channeling cartridge housing, which can be inserted into a housing holder in a water line and which, on the outer circumference of the cartridge housing, has at least one encircling annular groove, in which annular groove is arranged a sealing ring, which has a sub-region of its ring cross section projecting radially outward beyond the annular groove, and having at least one component, which is assigned to the insert part and, on its end side which is directed toward the insert part, has at least one retaining protrusion, by which retaining protrusion the component, in a latched position on the outer circumference of the cartridge housing, is latched to the insert part to form a unit.
DE 297 03 335 U1 has already disclosed a sanitary insert part which is of the type mentioned in the introduction and is designed in the form of a backflow preventer. The previously known insert part has a cartridge housing, which can be inserted into a housing holder in a sanitary water line. The outer circumference of the cartridge housing has provided on it at least one encircling annular groove, in which annular groove is arranged a sealing ring, which has a sub-region of its ring cross section projecting radially outward to a small extent beyond the annular groove, and therefore the sealing ring can seal the annular gap between the outer circumference of the cartridge housing and the inner circumference of that line portion which forms the housing holder. The previously known insert part, on its inflow end side, bears a hat-shaped filter screen which, on its end periphery which is directed toward the insert part, has at least one retaining protrusion, which is designed in the form of an annular wall and by which the filter screen can be latched on a reduced-external-diameter housing protrusion, which projects from the end side of the insert part, to form a unit comprising the insert part and the filter screen. Since the latching element on the insert parts, on the one hand, and on the filter screen, on the other hand, are adapted to one another, the sanitary insert part is intended solely for use in conjunction with the filter screen and at least the filter screen cannot also be used with such insert parts as were originally intended for use without an inflow-side filter screen and which therefore do not have the necessary end-side mating protrusion.
EP 0 593 490 B1 already discloses a sanitary insert part which is likewise designed in the form of a backflow preventer and in the case of which the cartridge housing of the insert part is connected in one piece, on its inflow side, to a hat-shaped filter screen. It is therefore the case that it is not possible for the insert part to also be used without a filter screen.
The previously known insert parts described above can be inserted, by way of their cartridge housing, into the housing holder provided in a sanitary water line. It is additionally also the case, however, that insert parts designed, in particular, in the form of backflow preventers are required for other application areas, for example in the water line of a water-consuming appliance.
In order to render such insert parts as versatile as possible, it may therefore be advantageous if the insert part can be used optionally with and without the component designed, for example, in the form of a filter screen and if the insert part, if required, can also be connected subsequently to such a component.